Those two, along with certain Porsches, do give the M3 a run for it's money. :

GTR is a 110,000 car. to much money for this comparison. at that point we which include a ZR1 and R8.....

i think AMG, RS5, and CTSV, are more on point with the m3. being luxury sports cars. and being well under 100k cars .

Sure, but I'm saying they become more viable as options if the M4 does turn out to be $85k. I can't speak for others, but for me, I'd be willing to pay another $15-20k to have a ~2.5 second 0-60 GT-R over a ~4.5 second M4. The Jaguar is another even cheaper option because it is more like $95k in its highest trim level of 495hp, granted its 0-60 isn't quite as stellar as the GT-R but it's one of the most beautiful new cars on the market, hands down.

And yes I know, these aren't drag racing cars and 0-60 times are certainly not the best qualifier for comparison, but they're a quick way to gauge overall performance.

The ZR1 is still "just" a Corvette, and to me it's overpriced for what you get. There is little justification in choosing it over a GT-R at its price point. The R8 OTOH is a good addition to the list, but in the higher trims (V10) they're going for more like $150k and again, the GT-R will outmatch them for $40k less.